[carbocation]

If you want to filter by grade level, why not just use a ready-made javascript script that computes an actual Flesch-Kincaid reading level [1]? This seems like reinventing the wheel, though I understand that can be the point of a weekend project.

[1] = e.g., https://github.com/cgiffard/TextStatistics.js

[Osmium]

Maybe because the Flesch-Kincaid reading level isn't a particularly good metric of anything other than sentence length and syllable count? Certainly not of "content" or "value" however you might define those concepts.

[carbocation]

Tell that to the author maybe? The author implemented the Flesch-Kincaid grade level algorithm in his plugin.

In other words, I'm not suggesting that he use Flesch-Kincaid; he already made that choice. I'm suggesting a way for him to not re-implement an algorithm that's already implemented in his language of choice.

[Osmium]

Ah, my mistake, my apologies. I thought the author was using a different metric.